Building Tailorable Hypermedia Systems: The Embedded-Interpreter Approach

Abstract

This paper discusses an approach for developing dynamically tailorable hypermedia systems in an object-oriented environment. The approach is aimed at making applications developed in compiled languages like Beta and C++ tailorable at run-time. The approach is based on use of: 1) a hypermedia application framework (DEVISE Hyper-media), and 2) an embeddable interpreter for the framework language. A specific hypermedia system is instantiated from the framework with the interpreter embedded in the executable. The specific hypermedia system has a number of “open points” which can be filled via the interpreter at run-time. These open points and the interpreter provide sufficient support to allow tailoring at run-time as well as compile-time. Among the types of tailoring supported are: 1) adding new media-types, 2) alternating editors for supported media-types, and 3) removing a supported media-type. The paper describes the framework and illustrates how the interpreter is integrated. It describes steps involved in tailoring a specific hypermedia system with a new drawing media-type, where graphical objects can be endpoints for links. Since the hypermedia framework uses a persistent object-store, a solution for handling persistent interpreted objects is presented. Finally, the approach is compared with other environments supporting tailoring.